1. Field of the Invention
This invention relates to a animal stunning device for use in an animal slaughter house operation and more particularly to improvements in the actuating mechanisms of such devices.
2. Description of the Prior Art
The related application discloses a humane animal stunner having a stunning element which reciprocates from within the stunner to a position outside the stunner, a support nose passageway which provides direction and support for the stunning element during operation, and a trigger assembly for initiating projection of the stunning element. The trigger is engageable with a pneumatic trigger valve that is operable to exhaust air to the atmosphere, and the stunner is actuated when the valve is opened to exhaust the air. The trigger mechanism includes a selectively actuable safety block which may be shifted between an operating position, enabling the trigger, and a safe position, preventing trigger operation.
Due to the potentially hazardous nature of the stunner, it is of utmost concern that the chances of inadvertent actuation of the stunning element be reduced as much as possible. The safety block associated with the trigger mechanism as disclosed in the above referenced parent application is useful for precluding actuation of the stunner when the latter is not in constant use; however, the operator may inadvertently fail to use the safety block or, alternatively, may accidentally depress the trigger at an inopportune moment.
Portable pneumatic fastener driving devices are occasionally provided with structure somewhat similar to the driving means used in animal stunners, and such fastener driving devices are sometimes provided with a concommitant actuating mechanism to deter accidental actuation. In the past, such a safety mechanism has comprised a mechanical, motion-transmitting linkage between the trigger and a outwardly extending, shiftable work contacting member. As the operator moves the fastener driving device to the work, the contact member shifts inwardly and the linkage moves to enable operation of the trigger. Consequently, the device is actuated only when both the work contact member and the trigger are shifted. Such actuating mechanisms are illustrated for example in U.S. Pat. Nos. 3,572,572, issued Mar. 30, 1971 and 3,784,077, issued Jan. 8, 1974.
Unfortunately, such mechanically linked actuating mechanisms are subject to wear, often to the point where actuation is possible by sufficient trigger pressure alone. Obviously, this condition presents a serious safety hazard which is even more dangerous when the operator is relying upon the mechanism to prevent such unwanted actuation. Furthermore, such linkages tend to jam when utilized in animal stunners because of the large amount of airborne foreign matter normally encountered in slaughter house operations.